2. THEY TEST COASTERS WITH WATER-FILLED DUMMIES.

Bill Kitchen, founder of U.S. Thrill Rides, says it can take anywhere from two to five years for a coaster to go from idea to execution. Part of that process is devoted to the logistics of securing patents and permits for local site construction—the rest is extensive safety testing. “We’re subject to ASTM [American Society for Testing Materials] standards,” Kitchen says. “It covers every aspect of coasters. The rides are tested with what we call water dummies, or sometimes sandbags.”

The inanimate patrons allow designers to figure out how a coaster will react to the constant use and rider weight of a highly-trafficked ride. The water dummies—which look a bit like crash test dummies, but filled with water—can be emptied or filled to simulate different weight capacities. Designers also sometimes use the kind of crash-test dummies found in the auto industry to observe any potential issues prior to actual humans climbing aboard.

4. ROLLERCOASTER TYCOON BROUGHT A LOT OF PEOPLE INTO THE BUSINESS.

The popular PC game, first released in 1999, allowed users to methodically construct their own amusement parks, including the rides. As a proving ground for aspiring engineers and designers, it worked pretty well. Jeff Pike, President of Skyline Attractions, says he’s seen several people grow passionate about the industry as a direct result of the game. “I remember when the game first got popular, I would go to trade shows and there would be kids looking to get into it using screen shots of rides they designed. The game definitely brought a lot of people into the fold.”

6. A COASTER’S SKYLINE IS KEY.

Brian Morrow, Corporate Vice President for Theme Park Experience at SeaWorld Parks and Entertainment, says that the looming curvature of coasters spotted as guests drive toward and enter the park is very purposeful. “It’s like a movie trailer in that we want you to see some iconic coaster elements, but not the whole thing,” he says. “You approach it with anticipation.”

8. WOODEN COASTERS ARE WEATHER-SENSITIVE.

If you’ve ever been on a wooden coaster that seems a little shaky from one trip to the next, check the forecast: It might be because of the weather. Pike says that humidity and other factors can shrink the wood, affecting how bolts fit and leading to a slightly shakier experience. “The structure itself can flex back and forth,” he says. It’s still perfectly safe—it just takes more maintenance to make sure the wood and fasteners are in proper operating condition. A well-cared-for wooden coaster, Pike says, can usually outlast a steel model.

10. DESIGNS CAN COME FROM UNUSUAL PLACES—LIKE JAY LENO’S CHIN.

The twisting, undulating tracks of coasters can often be the result of necessity: Pike says that trees, underground piping, and available real estate all inform designers when it comes to placing a ride in a specific park. But when they have more freedom, coasters can sometimes take on the distinctive shape of whatever happens to be around the designers at the time of conception. “We had a giant piece of land in Holland that just had no constraints, and we were sitting around talking," Pike says. “And we started talking about Jay Leno’s chin.” The ride was a “loose” representation of the comedian's jaw, but “it is there.”

12. THE FUTURE IS VERTICAL.

Biggest, fastest, longest—coasters are running out of superlatives. Because rides can only be designed with so many drips, rolls, or G forces, some companies are looking to the sky for their next big idea. Kitchen has been overseeing design of the Polercoaster for years: It’s a sprawling, skyscraper-esque ride that uses electromagnetic propulsion to carry riders upwards instead of across horizontal tracks. “We want to put it in places where land is very expensive, like the Vegas strip,” he says. “You can only do that if it takes up a lot less space.” Kitchen believes it’ll be another two years before ground is broken on the project, which is set to exceed the 456 feet of the current tallest ride, Kinga Ka at Six Flags in New Jersey. “It’ll be the world’s tallest—and hopefully the most fun.”